The Diagnostic Significance Of Trophoblast Cell-Surface Antigen-2expression In Benign And Malignant Thyroid Lesions

Context: Thyroid cancers are the most common malignancy of the endocrine system. Over-expression of trophoblast cell-surface antigen 2 (TROP-2) in various tumors has been found to correlate with poor prognosis and aggressive tumor behavior. Aims: The aim of this study was to evaluateTROP-2 expression in thyroid neoplasms. Subjects and Methods: This study contained 152 cases, including 48 follicular nodular disease (FND), 29 follicular adenoma (FA), 57 papillary thyroid carcinoma (PTC), 12 follicular thyroid carcinoma (FTC), 3 medullary thyroid carcinoma (MTC), 2 poorly differentiated thyroid carcinoma (PDTC) and 1 undifferentiated thyroid carcinoma (UDTC). TROP-2 expression was investigated via immunohistochemistry in sections prepared from paraffin blocks of the cases. Results: The cases comprised 32 (21%) males and 120 (79%) females with a mean age of 46.8 years (range, 15-85 years). TROP-2 expression was observed in 74.6% of the malignant lesions of the thyroid except for medullary carcinoma, poorly differentiated and undifferentiated thyroid carcinoma. Immunoreactivity was 3.4% in FA, 41.7% of cases with FTC and 81.8% in PTC follicular variant (PTC fv). The difference between FA/FTC and FA/PTC follicular variant were both significant (P < 0.005, P < 0.001, respectively). There was no difference between FTC/PTC fv (P = 0.089). Conclusion: TROP-2 can be considered a useful marker for distinguishing PTC fv cases from follicular nodular disease and follicular adenoma cases because of its high sensitivity in the identification of papillary carcinomas of the thyroid.